Whereas this definition of SARI may prove practical to mount sentinel SARI surveillance systems, it is unlikely to provide relevant information for intensive care physicians regarding the nature of infections, the spectrum of severity, or the diagnostic and treatment strategies used for the subset of patients that are ultimately admitted to intensive care units. Only a subset of the SARI patients as defined by WHO will require ICU admission for oxygen therapy or positive pressure ventilation; a smaller subset will develop an acute respiratory distress syndrome (ARDS) and an even smaller proportion will require adjunctive treatments such as nitric oxide, ECMO, use of prone position or high frequency oscillation (HFO). Obtaining accurate information on the epidemiology of ICU-SARI and how these patients are currently diagnosed and treated will help us to understand the factors associated with progression from acute respiratory infections to the most severe forms of critical illness such as ARDS, septic shock, or multiple organ failure.